1. Field of the Invention
The present invention relates to a method of and apparatus for booting a personal computer system and, more particularly, for quickly booting a computer system, in which a boot configuration information is created and saved in a disk for future boot, and the saved boot configuration information is reused upon the request of the subsequent boot.
2. Description of the Related Art
FIG. 1 shows a block diagram of the system architecture for a conventional personal computer system, comprising a central processing unit (CPU) 1; a read only memory (ROM) 2 for permanent storage of basic input output system (BIOS) and the initial states of internal devices, a random access memory (RAM) 3 for temporary storage of information; a micro computer (MICOM) 4 for controlling peripheral devices such as a keyboard input device, a mouse input device, and a power supply 7; a hard disk (HDD) 8 for providing a secondary information storage; a disk controller 5 for controlling HDD; a video output display 6 for displaying information; and a power supply 7. When power is applied to the computer system, the computer system starts to be booted to load an operating system (OS) and thus is brought into a known useful state in which application programs can be executed. This procedure is generally called “booting”. An operating system is a software that provides resource management on a computer system, including basic tasks such as process execution, memory management, and file management. Examples are MS-DOS, Windows95, OS/2, and UNIX. Execution of user applications is based on these basic functions of the operating system.
The boot process of an IBM PC in which MS-DOS operating system is already installed is as follows. When a user turns the personal computer power switch on or presses a reset button, a power-on self test (POST) is performed by ROM BIOS codes to diagnose each component of the personal computer. Next, a file called MSDOS.SYS is loaded and executed, and another file called IO.SYS is then loaded and executed to perform certain preliminary functions related to management of such peripheral devices as keyboard, disk, and display. And then, a command preprocessor or COMMAND.COM is loaded into a memory that receives, interprets and executes user commands. A file called CONFIG.SYS that specifies devices possibly connected to the personal computer is loaded and ASCII statements contained therein are executed to load device drivers and initialize them. Finally, another ASCII file called AUTOEXEC.BAT is loaded and then programs that are listed therein are executed, thereby preparing the personal computer for use.
There two kinds of boots; “cold boots” and “warm boots”, which rely on the state of the computer system when the boot operation is requested. A “cold boot” is performed when power is applied to the computer or a reset button is pressed. When an operating system is loaded in memory already and the computer system is powered on already, a user may request a “warm boot” by entering a predefined sequence of key strokes, e.g., <Ctrl>+<Alt>+<Del>. The BIOS codes include a plurality of computer routines for controlling devices such as a system clock, video output display 6, disk controller 5, and keyboard and thus provide a low-level interface to these devices. The BIOS is generally stored in a Flash ROM.
Shortly after power on or a reset button is pressed, the CPU begins executing the ROM BIOS codes. The BIOS codes for POST are, first, executed to diagnose and initialize devices attached to the computer system and obtain the status of the devices.
When a “warm boot” is requested or a reset button is pressed, it is desirable that the time required for the boot process is reduced to force the computer into a ready state as quickly as possible. The boot process is usually called “quick boot”, which is achieved by simplifying some device diagnosis processes or loading the device status information that was obtained at the preceding boot time from a storage medium such as disk. Because the quick boot means a boot process in which some POST operations, e.g., memory test are skipped, the quick boot is generally referred to as “quick post”.
FIG. 2 is a flowchart of the quick POST in an IBM personal computer system in which Windows95 is installed according to the conventional art. When the computer system is powered on or a reset button is pressed (S11), the Windows95 is loaded into a memory after execution of a normal POST process (S12). To be specific, once the POST process is performed, ASCII statements in CONFIG.SYS and AUTOEXEC.BAT are executed sequentially and WIN.COM is then executed to load Windows95. While Windows 3.1, a previous version of Windows95, is loaded after the personal computer is booted on the basis of MS-DOS, Windows95 installed PC is booted and Windows95 user interface is provided directly.
Once the boot operation is completed, a basic boot information is saved to a disk for future quick POST process (S13). After that, if a user requests a “quick boot” to reboot the personal computer (S14), the above-mentioned quick POST process is performed to reduce the time needed to complete a normal POST process. As another method, the POST process execution is skipped by using a basic boot information that was created and saved in a disk immediately after the preceding POST process is completed.
However, the conventional quick boot relies on the POST process, e.g., the omission of memory test. In other words, in the conventional quick booting method, the same operations as those of normal boot process are still performed after the quick POST process. Therefore, in case where there are a lot of ASCII statements in CONFIG.SYS and AUTOEXEC.BAT, the quick boot of the conventional art is not effective to reduction of the boot time.
According to the conventional booting method, in Windows95 installed personal computer system, working environment or all information stored in memory are saved to a disk for the subsequent quick boot. If memory size is larger than 32 MB, the amount of data to be saved to the disk becomes too large. As a result, the subsequent booting by reloading the saved data into the memory may be even slower than a normal boot.